Nancy Pelosi is making another play for her fellow Californian and close friend, Rep. Anna G. Eshoo, to be ranking member on the Energy and Commerce Committee.

The Minority Leader sent a letter to colleagues on Thursday afternoon, just as the House was finishing legislative business before November. That's when the full Democratic Caucus will vote for either Eshoo or her colleague, Rep. Frank Pallone Jr., D-N.J., to win the party's top spot on the powerful committee .

With competition stiff between the two lawmakers, Pelosi stunned colleagues once already back in late February, in the very early days of the campaign to succeed retiring ranking member Henry A. Waxman, D-Calif., by penning a letter in support of Eshoo. It's not common for a member of leadership to get involved in such dynamics publicly. Minority Whip Steny H. Hoyer, D-Md., was initially acknowledged to be working behind the scenes for Pallone, which he felt compelled to all but admit after Pelosi took a public stance.

The fight will ultimately come down to personal relationships and cultivated loyalty, not to mention financial support doled out through leadership political action committees. It will also be a referendum on the seniority system, for which many members have significant deference. Pallone is the current No. 3 Democrat on Energy and Commerce, with Eshoo coming in at No. 5.

Pelosi's backing doesn't always make the difference: The last time she vocally backed a candidate in a leadership race was in 2006, when she supported her close ally, the late-Rep. John P. Murtha of Pennsylvania, over Hoyer to be the majority leader in the new Democrat-controlled House. Hoyer, of course, handily won that race.

Her newest letter also comes out on the same day that 50 of Pallone's whips and core supporters signed onto a Dear Colleague memo aimed at rising their preferred candidate's profile in the weeks before the decisive vote by the full caucus.

Read Pelosi's case for Eshoo here:

Dear Colleague,
It is with great enthusiasm that I write to you once again to endorse Anna Eshoo to lead the Energy and Commerce Committee – the “Committee of the Future.”
As I said in my letter of February 27, Anna’s priorities in Congress reflect the future of America’s vibrant and competitive environment.
Anna’s leadership, vision, values and progressive commitment to the future gives us an opportunity to newly invigorate the debate.
Since my February letter, Anna has listened to Members, reflected their values and gained their strong support – more than 105 commitments, a majority of the Caucus.
Thank you for your consideration.
best regards,
NANCY PELOSI
Democratic Leader